[sdiy] Wishing for Interdesign.....wish granted?

[Steve Lenham]

It's a glorious day here in the southern UK, too hot to work, and this 
thread jogged a memory...with quite exciting results.

I recalled seeing that Zetex (UK maker of semis, mainly discrete and SSI) 
offered a semicustom chip process akin to that described. And they do:

http://www.zetex.com/3.0/a5-3.asp

...the 700 series. It looks like Zetex do the chip fabrication but refer you 
to "partner companies" for the design and liaison. So, scroll down to the 
list of partners and we find our friends(?) OnChip Systems, well known in 
these parts as the modern reincarnation of Curtis Electromusic. Certainly an 
indication that the process is good for "our kind" of device - perhaps even 
that used for the more recent CEMs.

But there's more.

The Zetex page credits design of the 700 series to a company called Array 
Design, so follow the link and root around a bit to end up at:

http://www.arraydesign.com/experience/index.html

which reveals that the chap behind Array Design is the original founder of 
Interdesign (not to mention also the designer of the NE555 and NE566!).

They have, for free download (http://www.arraydesign.com/700series.html), a 
192 page manual very similar to that which Paul describes, and the Zetex 
page even refers to "colour coding of the metal interconnect" during 
design - not a million miles from the old coloured pencils.

I haven't had time to read any further yet, and all the usual worries about 
price/MOQ/etc. still apply, but let's savour for a moment the idea of being 
to access the same IC process which brought us CEMs in the first process and 
which is still used by Curtis himself...

If it still looks good in the morning, perhaps a discussion of the best next 
move might be in order?

Have a good weekend,

Steve L.


----- Original Message ----- 
From: "Paul Schreiber" <synth1 at airmail.net>
To: "karl dalen" <dalenkarl at yahoo.se>; "Colin f" <colin at colinfraser.com>; 
<synth-diy at dropmix.xs4all.nl>
Sent: Friday, May 27, 2005 4:38 PM
Subject: [sdiy] Wishing for Interdesign.....


> Interdesign was exactly what we need now: a generic "500-in-1" (Radio 
> Shack reference) array of generic analog "building blocks" on 1 die. You 
> used a 2-color pencil (really!) and drew out the "schematic" on a giant 
> 36" x 48" master template. Then, they added 2 metal layers and you had a 
> custom IC.
>
> The down-side was you had to test them yourself ("No Time to Test 
> These!"...obscure reference no one under 47yrs old will get)
>
> The cost was low: $750 and that got you like 40 packaged parts! Of which 
> 30 worked :)
>
> In fact, the early CEM chips (3310/20/30/40) are actually Interdesign 
> parts! The reason: Doug Curtis, the designer, won a magazine contest with 
> them and as 1st place got 100pcs free. The rest is history.
>
> The later parts (3396, etc) are done on a Doug Curtis designed array (4X 
> larger than Interdesign), the fab was AMI. In Doug's office his winning 
> entry is framed on the wall.
>
> BTW: Interdesign had GREAT app notes in a 5" ring binder. They may turn up 
> on eBay/flea markets. About 8 are by Doug on the OTA gain cell (patent has 
> expired....hmmmmm.......)
>
> Paul S.
>
>
>
>